The '''National Security Agency''' ('''NSA''') is an intelligence agency|intelligence organization
of the United States government, responsible for global monitoring, collection, and processing of information and data for foreign intelligence and counterintelligence
purposes – a discipline known as signals intelligence
(SIGINT). NSA is concurrently charged with Information assurance|protection
of U.S. government communications and information systems against penetration and network warfare.
Although many of NSA's programs rely on "passive" electronic collection, the agency is authorized to accomplish its mission through active clandestine operations|clandestine means
[''Executive Order 13470 – [http://www.gpo.gov/fdsys/pkg/WCPD-2008-08-04/pdf/WCPD-2008-08-04-Pg1064.pdf 2008 Amendments to Executive Order 12333], United States Intelligence Activities'', July 30, 2008 (PDF)]
among which are...